


Sun Crossed Moon

by SoloShikigami



Category: Undertale (Video Game)
Genre: Bondage, Cunnilingus, Incest, M/M, Mildly Dubious Consent, Multi, Praise Kink, Self-Hatred, Tentacle Sex, Tentacles, Threesome - M/M/M
Language: English
Status: Completed
Published: 2020-09-06
Updated: 2020-09-06
Packaged: 2021-03-06 16:29:06
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,273
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/26311933
Author URL: https://archiveofourown.org/users/SoloShikigami/pseuds/SoloShikigami
Summary: Ever since leaving Nightmare, Cross has become Dream most loyal soldiers. He would do anything for his new master, and Dream wants to reward him. He also has a need for positive energy to feed from, but Cross' negative feelings towards himself also gives a unique opportunity to allow a negativity-fed monster to benefit as well. Like a good brother, Dream invites his brother Nightmare over for a good meal, and Cross can only ultimately reap the benefits.
Relationships: Dream/Cross/Nightmare, Sans/Sans/Sans
Comments: 5
Kudos: 130





	Sun Crossed Moon

**Author's Note:**

  * For [Muskka](https://archiveofourown.org/gifts?recipient=Muskka).



Cross walked into the room he was instructed to go to. Inside, Dream was seated in a golden seat. The arms were low, the seat curved into the same smiling shape of its occupant’s mouth, Dream had one leg crossed over the other, one elbow propped on the padded chair arm, his head resting against his hand as he watched with sparkling eyes as Cross came closer.

His beloved soldier, his loyal fighter, dropped to one knee, sitting on his heel, one hand on his chest, his head bowed low, and his eyes closed.

“I have come as you asked, Dream,” Cross murmured.

“You have, thank you,” Dream replied. “You are always so good, Cross, you listen to instructions and follow them to the letter.”

Cross said nothing.

“I appreciate that you are loyal to me.”

Again, Cross stayed silent, though Dream could see him tense. He sighed, uncrossing his legs and standing up, closing the space between him and his soldier.

“You still feel guilty over what happened between you and Nightmare,” Dream said, standing over Cross. “You know there are no hard feelings there. Even my brother and I have our disagreements, and sometimes they get extreme, and yes, losing you was quite a loss, but I have come to appreciate why that is such is a loss for him.”

Cross stayed silent, but Dream could feel the negative emotions warring inside of him.

“I say that because I have come to learn how amazing you are, Cross,” Dream said, dropping to one knee himself and curving a hand under Cross’ chin, lifting his face. “And while you are an amazing solider, a stalwart fighter, there is so much more to you than you give yourself credit for.”

Cross’ eyes had slowly re-opened. Dream gave him a small smile upon seeing the conflicting emotions there. He leaned forward, taking note of Cross’ aborted attempt to back away, but in the end he stilled as Dream brushed his mouth over his ever so slightly.

“I’m hungry, Cross,” Dream murmured. “And I would like your help.”

“Surely Blue would be a better partner,” Cross said, his voice shaking slightly.

“Mmm, no, not for this,” Dream said, backing away and standing up, giggling a little to himself as Cross leaned forward slightly. “Besides, I think you deserve a little fun and feeling good for yourself. Stand up, please.”

“I don’t understand,” Cross said, obeying Dream’s command.

“I know,” Dream said, moving in close again, wrapping an arm around Cross’ waist and pulling him close, while his other hand caressed his skull, then moved down the back of his neck and down one arm, weaving their fingers on one hand together as he spoke. “I believe you are letting the remnants of your old life cause you too much pain. On one hand, that’s good for me, because the more I can make you feel good, the more energy I can feed off of. However, I feel that we are presented with a bit of a unique opportunity where your current state of mind can also service someone else.”

Cross tilted his head, looking confused, but then when he noticed Dream’s eyes flicker over his shoulder, he tensed when he felt another presence in the room. Familiar dark tentacles dripping with dark magic slithered around his ankles and slightly up his calves, one found its way around his waist, and one slithered down his arm and wrapped around his wrist.

“Hello, Cross, long time, no see,” the familiar voice of the evil monster rumbled against his skull.

Cross panicked, his body seizing, caught between wanting to fight Nightmare off, make sure Dream was safe, but since Dream was there right in front of him, and also holding onto him firmly, he couldn’t move without hurting him, and the very last thing Cross would ever do is hurt Dream.

"Mmm, you still fear me, Cross?" Nightmare murmured. "Good. That is quite delectable."

"Be nice," Dream said flatly, though clear warning was behind it.

"I thought you said I would be able to feed, too."

"Yes, but take it easy, be patient," Dream chastised before turning his full attention back to Cross, smiling and giving him a comforting light squeeze. "I understand why you're afraid; know that I am not going to let any harm come to you."

"B-but," Cross stammered, struggling against both holds. "H-he can't be trusted!"

"Yes, he can," Dream said.

"No!"

"You can trust me, Cross," Nightmare said with a sigh and a roll of his eyes. "I am not here to harm anyone. Punish you a bit for leaving me, yes," he wrapped a thin tendril around Cross' neck, the hold firm for a moment, and he shuddered with the influx of fear, but then released him. "But I will not harm you or my brother."

"W-why?"

"With you on Dream's side, it has been more difficult for me to fulfill my objective," Nightmare growled. "However, it seems my dear brother still does not wish for me to perish, so he has given me this opportunity to at least nourish myself," Nightmare smirked and leaned forward to nuzzle at Cross' temple. "I will make it worth your while, Cross, because I believe I have yet to show you the appreciation you deserve for what you had done for me as my loyal follower."

"N-n-no, please, I, I didn't do anything," Cross gasped.

"Aw, Cross, you have, you are such a good soldier," Dream said, caressing his skull again. "You have obeyed my every command from day one."

"I-it's my job," Cross said, shivering as Dream's fingers made their way down the back of his neck, touching on the spots he knew were sensitive.

"But you go above and beyond," Dream pointed out. "Plus you are very kind to Blue and Ink and everyone else here."

Cross grimaced, searching his mind for some form of denial, but those light fingers rubbing at his cartilage were making it difficult, as well as Nightmare's tentacles, while still rooting him to the spot, were writhing and slowly working their way over his limbs.

"You always did have that streak of kindness," Nightmare admitted. "It was what set you apart from the others, and it's something I always liked about you."

Getting praise from Nightmare was unheard of, at least like this. One would get a gleeful chuckle and perhaps a "good job" after completing a mission, but not only was Nightmare's tone of voice sweet and gentle, there was an undercurrent of something that Cross couldn't describe, but it was doing odd things to his magic.

"He's so cute," Dream said, his fingers leaving Cross' neck, now trailing across his collarbones.

"He is," Nightmare agreed,

"I am not!" Cross exclaimed, feeling like he finally had a foothold again and struggled against them again, harder this time.

Dream and Nightmare were not deterred; Nightmare tightened his hold and this time his fingers closed around Cross' neck. Dream had backed off a little, but he continued to hold Cross' hand. Once Nightmare had him firmly held again, Dream moved in close once more, looking into Cross' eyes and feeling the energy coming off of him. It was a mix of pain and desire, want and shame, pleased but devastated.

"You have the freedom to reject us," Dream reminded him. "Though, what I am feeling from you is telling me that is not what you want."

"Oh, he wants us, but he is ashamed for it," Nightmare chuckled. "Ahh, that is a delightful feeling to feed from. You do actually like all of this, the praise, denying, being bound but fighting against it. You're getting off on this, aren't you?"

"Nighty, don't push," Dream warned.

Cross was blushing and couldn't meet Dream's eyes.

"I deserve to be punished," he murmured after a few moments of silence.

"But you also deserve praise, to feel good," Dream said, leaning in and again brushing Cross' mouth with his own as he spoke. "Remember our first nights together, where I peeled back your layers, slowly broke you down so I could help find the root of your wounds, to help you rebuild back?"

Cross trembled at the memories, his mind flashing to the difficulty and the pleasure of his nights with Dream, but shame and fear crept back in as he was reminded that Nightmare was there, listening, and he could feel him just as much as Dream could.

"You know, Dream, I thought you were a little crazy and a bit too hopeful about this, but I see what you mean," Nightmare chuckled. "I don't know about you, but I am having a wonderful meal."

"As am I," Dream smiled at Cross. "Though I think Cross deserves a little relief now, what do you say?"

"I think that is a wonderful idea," Nightmare murmured, bending to kiss the back of Cross' neck.

Cross let out a gasp; Nightmare's mouth was cool, his tongue slipped between the discs in his neck, following the same patterns as Dream's fingers from a few moments ago. He tried to stifle a moan, but it slipped as his legs began to feel shaken.

"You are so cute," Dream murmured, nuzzling Cross' jaw.

"A-am n.. mph... am not," Cross forced out.

"You are," Nightmare said, moving down his neck.

Cross' denial was choked off as Dream began to reach under his shirt to caress his ribs. There seemed to be an unspoken sort of communication going on between Dream and Nightmare, for as Dream slowly let go of Cross' hand, Nightmare was ready to seize his wrist and hold it tight. Dream kissed Cross, his hands pushing down his coat, Nightmare helping by letting go of Cross just enough to slip the garment away, and he tossed it aside. He had left some of his extra vestments in his room, so he only stood between them in his thin, white t-shirt and shorts. Nightmare brought his hands up, holding them on either side of his head, leaving him open and vulnerable to whatever the two brothers had planned. Dream backed away for a moment, and Nightmare also gave him some space. He felt Cross tense, holding himself still, his mixed and conflicted emotions rolling off of him in waves.

"You're being a good boy, Cross," Dream said, smiling at him warmly. "I did promise you some relief."

"But first, you gotta give us something," Nightmare said, and Cross could hear the evil grin spreading across his face.

He stayed silent, wanting to still be Dream's perfect soldier, but he couldn't stop the small cry of surprise when Nightmare began wrapping tentacles around the inside if his legs, high up near his pelvis. The thick appendages rubbed along his bones over his clothing, Cross tried to contain his magic, but he was already keyed up and his body was begging for more.

"Mmm, delicious, that shame and fear," Nightmare chuckled. "Honestly, though, you still think I'm here to hurt you or Dream? Feh."

A tentacle slid from his tailbone, between his legs, to his front and Cross shuddered as the feeling. Nightmare even pulled at his legs so they spread a little wider, but still kept him upright.

"Y-you... c-can- oohhh," Cross tried to protest, but another groan took over.

"Oh, sweetie," Dream said, moving in close again. "Relax, you deserve this, it'll be okay, I promise."

"P-please," Cross whispered, feeling torn between asking for relief and asking them to stop.

But he didn't want them to stop, not really, and they knew it.

"Let's see what my loyal soldier has for me today, hm?" Dream asked, one hand slipped below the waistband of his pants, Nightmare's tentacle moving aside and letting him push the shorts down to the floor.

"This should be interesting," Nightmare murmured, knowing what he felt and waiting for his suspicions to be confirmed.

Again, a mix of shame and desire washed over Cross as the cooler air of the room hit the mound of magic his body formed, evidence of his desire making the outer rims of his labia shine with wetness.

"Oh, my," Dream murmured, glancing down, then slowly, gracefully dropping to his knees. "Cross, so beautiful, as always."

Cross tensed again with the intention of pulling away, blushing and feeling foolish, but a soft, warm tongue lapped at slit that split his magic and the thought was lost. Dream hummed, pressing his tongue in more firmly, the tip brushing through folds of magic, tasting the wetness, and following it to where it was flowing from. Cross' breath began to come out in gasps and pants when he allowed them to escape, still trying to keep it in, and his struggle against Nightmare's hold started again.

"Oh, please," Nightmare sighed, moving in close again, wrapping his arms around Cross' middle, not only to hold him a little more still, but to pull him into Nightmare's body, gently, like what one would expect from a lover. "Just, relax, let him make you feel good,"

Cross let his weight lean back against Nightmare, despite himself, as Dream continued to swirl and press his tongue against his magic, coming so close to his clit and bypassing it, repeating the teasing motions until Cross started to let out small, almost whimpering sounds.

"Don't tease too much, brother," Nightmare said.

"You're right," Dream agreed.

Cross trembled in anticipation; Dream moved in closer, again lapping gently, but then his tongue began to slip close to Cross' entrance, then carefully pressed inside, Dream's nasal aperture nuzzled against his clit as he did so.

"Fuck!" Cross groaned, pressing back into Nightmare.

"Shh, shh, relax, I got you," Nightmare murmured, watching Dream work from over Cross' shoulder.

Dream hummed as he pleasured Cross, enjoying the good feelings coming off of him. He wished that there weren't the small shreds of shame that went with them, but since those would go to his brother to feed off of, he couldn't worry too much about it. He filed it away in his mind as something to work on with him when they were along together, but for now, it still didn't keep Cross' legs from trembling as Dream brought him closer and closer to his peak.

"Please, Dream, please," Cross gasped, trying and failing to move into that gently thrusting tongue.

"I think he's getting close, brother," Nightmare said.

Dream pulled away slowly, smiling up at them both. Nightmare smirked at the surge of disappointment and loss from Cross, and Cross was looking at Dream in a mix of disbelief and worry.

"You didn't do anything wrong," Dream assured him, holding his face in his hands gently before leaning in for a kiss. 

Cross whimpered, tasting his magic on Dream's tongue, and before he could say anything or even think, he felt one of Nightmare's tentacles moving further up his leg.

"H-hey!" Cross started to protest.

"What?" Nightmare all but demanded.

Cross struggled weakly again, even weaker than before.

"You can still change your mind, you know," Nightmare's voice was a little gruff, he sounded annoyed, but he reeled it in quickly. "While I'm loving the negative portion you're punishing yourself with, I'm not here to hurt you."

"N-no, please," Cross begged.

"What is it?" Nightmare asked in a gentler tone.

"I... I... kinda... like... struggling..."

The shame that went with the confession sent a thrill through Nightmare.

"We can accommodate," Dream said. "But I believe my brother was looking to be... intimate as well."

"Oh for Star's sake," Nightmare growled. "Cross, I want to fuck you. Are you okay with that?"

"Yes."

The answer was so quick even Dream was startled.

"Wha- wait, really?" Nightmare asked, unable to believe it.

"I mean it," Cross said, his voice clear and certain for a moment, but then he went back to soft murmurs and blushing embarrassment. "But I... uhm... still want to kind..."

"You want me to work for it?" Nightmare asked with a smirk.

Cross nodded.

"All right."

Nightmare tightened his hold on Cross again and his tentacle immediately swiped through Cross' cunt, making the other cry out in a mix of pleasure and dismay.

"So you want me to fill you up, Cross? Are you going to show me how you service your master?" Nightmare asked

"N-not my m-m-master," Cross forced out.

"Suit yourself."

Cross cried out as the tip of the tentacle slipped into his entrance, wiggling around a little. Dream watched, intrigued; feeling and seeing Cross struggle was a bit of a thrill for him, too, but only because he knew there was no harmful intent involved. Nightmare was being gentle, but firm, Cross was struggling, but he was enjoying it despite his shame. It was a wonderful balance for all involved.

"Ready for more?" Nightmare asked.

Cross barely got a slight nod out before the tentacle pressed in further, and Cross wailed at its thickness inside him. Nightmare moved quickly, pressing in deeper with each thrust. Cross' legs gave out a moment later, but Nightmare held him, wrapping his tentacles around his knees to keep him steady.

"It's so nice to see you like this, Cross," Dream said, moving in close again to touch Cross' face and kiss him. "You're so hot when you're being pleased. It feels good, doesn't it?"

Cross couldn't answer, tears threatening to fall.

"Aww, my good soldier, it's okay," Dream murmured, kissing Cross again and reaching down to gentle fondle his clit. "You're about ready to cum for us, aren't you?"

The words were barely making any sense to Cross, he was lost in a world of pleasure and humiliation, and he was put there by the one he betrayed and abandoned, just barely grounded by the face of salvation that stood before him, offering words of encouragement, healing, and hope.

"Cum for me, my loyal soldier."

Nightmare thrust in particularly hard, focusing his magic to make the tentacle thicker, and Cross screamed. His body shook as Nightmare continued to thrust, though gradually slowing down, Dream’s fingers still rubbing his oversensitive nub as his mouth moved over his to silence some of his cry. The world swam for a moment, an odd mix of black and gold.

"Such a good boy," Dream said. "You can rest now, Cross."

Cross' body suddenly went limp, his mind shutting down, the unconscious skeleton sagging in the tentacles that trapped him.

"Wow, that was something," Nightmare said, carefully lowering Cross to the floor and releasing him as Dream fussed over the passed out skeleton.

"Yes, it was," Dream agreed, reaching for Cross' discarded jacket and folding it before lifting his head to slip it underneath. Dream took off his own golden cloak and covered him as his body began to tremble, but Dream suspected it was due to the overexertion and not so much from cold.

"I appreciate the opportunity to share such a meal, I suppose I should thank you," Nightmare said.

"It would be nice," Dream beamed up at him.

Nightmare glanced around, moved to Dream, and quickly bent and dropped a kiss on the top of his skull.

"You tell anyone I'll fucking kill you."

"I understand, Nighty."

"Shut up."

Nightmare left, and Dream scooped Cross into his arms and brought him to the bedroom, laying him down carefully. After looking him over and cleaning him up a little, Dream got into bed and pulled him close, cuddling him, calming the trembling that began to rattle his bones.

After a few minutes, Cross sighed, snuggling into Dream, and the other could tell that he was at peace - at least for now.

"Sleep well, my good soldier."

**Author's Note:**

> Like what you read? Please check out my social media for more fun!  
> [ My Tumblr](https://soloshikigami.tumblr.com/)  
> [ My Twitter](https://twitter.com/SoloShikigami)


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